Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to an AC power
cord having an improved connector.
In the drawings:-
Fig. 1 is a simplified diagram showing the
installation of a conventional AC power cord wi-th a 3-pin
plug;
~ ig. 2 is a simplified diagram showing the
installation oE an AC power cord according to a preEerred
embodiment oE the present invention;
Fig. 3 is an enlarged view of the main part of a
bushing unit of the AC power cord shown in Fig. 2;
Fig~ 4 is a sectional view of the main part of
the bushing unit containing the AC power cord in another
preEerred embodiment of the present invention; and
Fig. 5 is a front view of a reinforciny ring of
the AC power cord shown in Fig. 4.
Fig. 1 indicates a simplified diagram showing
the installation of a conventional AC power cord 5
provided with a 3-pin plug 4. Typically, the AC power
~ 20 cord 5 and 3-pin plug 4, of which the latter has an earth
; terminal 1, a live terminal 2, and a neutral terminal 3,
are installed, for example, at the rear panel 7 of a main
unit 6 via a bushing 8, whereas the earth line 9 of the AC
power cord 5 is secured, for example, to a bottom plate 10
of the main unit 6 by a grounding screw 11.
In other words, the earth line 9 in the main
Ullit 6 should be grounded only after securing the AC power
cord 5 with a bushing 8, thus requiring at least two
assembly operations to be carried out. In addition, since
the AC power cord 5 cannot be easily positioned due to the
specific structure of the bushing 8, when securing the
cord to the main unit 6, the AC power cord installation
; work cannot be smoothly performed.
It is an object of the present invention to
provide a connector which simplifies the attachment of a
power cord to an electrical apparatus.
The present invention provides for
simultaneously securing an AC power cord including an
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earth line to an electrical device, in a housing including
a panel having an opening formed therein for receiving the
power cord therethrough, a device comprising an insulated
bushing formed on the AC power cord, the bushing having a
base for juxtapositioning with the panel so as to extend
into the opening the base including a notch for engaging
an edge of the opening to position the bushing on the
panel, an earth terminal, connected to the earth line of
the AC power cord, to provide a ground to the electrical
device, and means for securing the earth terminal to the
panel to electrically connect the earth terminal to the
device through the panel.
The present invention further provides a system
for simultaneously securlng an AC power cord including an
earth line to an electrical device, comprising, a main
housing receiving the electrical device and including a
panel, the panel having an opening Eormed therein for
receiving the power cord therethrough, an insulated
bushing formed on the AC power cord, the bushing having a
base juxtaposed with the panel and extending into the
opening, the base including a notch which engages an edge
of the opening and positions the bushing on the panel, an
earth terminal, connected to the earth line oE the AC
power cord, to provide a ground to the electrical device,
and means for securing the earth terminal to the panel to
electrically connect the earth terminal to the device
through the panel, the means for securing and the
engagement of the notch with the edge of the opening
collectively secure the bushing to the panel.
With reference to Figs. 2 to 5 of the attached
drawingsl preferred embodiments of the present invention
are described below.
In Figs. 1 to 3, parts which have the same
functions as those of the conventional unit shown in
Fig. 1 are indicated by the identical reference numerals,
and therefore, a detailed description of these parts has
been omitted.
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In Figs. 2 and 3, reference number 12 indicates
a plastic-moulded AC power cord connector provided with a
groove 15 receiving an Pdge 14 of an opening 13 formed
through a rear panel 7 of the main unit or housing 6, an
insulating bushing 12 also being moulded around the earth
line 16 and live and neutral power line terminals 17 o
the AC power cord 5O
Reference number 18 indicates an earth fixing
terminal which is connected to the earth line 16 and
secured to the molded plastics oE the connector 12. This
terminal i5 secured to a tapered hole 21, which is formed
through the rear panel 7 of the main unit 6, by a self-
tapping screw 20 inserted through a washer 19 in the
arrowed direction A.
Accordingly, since the earth Eixing terminal 18
is mechanically secured to the rear panel 7I this terminal
will electrically remain at the same potential as that of
the earth line 16 of the AC power cord 5, and as a result,
the main unit 6 will remain grounded.
The method of securing the AC power cord 5 to
the main unit 6 is described below.
First, the AC power cord connector 12 is
inserted into the opening 13 of the rear panel 7 of the
main housing 6, and then the groove 15 of the ~C power
cord connector 12 is engaged with the edge 14 of the
opening 13 so that the connector 12 can be correctly
positioned~ This allows the hole 21 in the upper part of
the open space 13 to perfectly match a screw hole 18' in
the earth fixing terminal 18. Next, the selE-tapping
screw 20 is inserted through the screw hole 18' via washer
19, and is then secured in the installation hole 21 so
that the earth fixing terminal 18 is secured to the rear
panel 7 of the main unit 6, and at the same tlme, the
connector 12 is also secured to the rear panel 7. As a
result, the AC power cord bushing 12 is secured to the
main unit 6 by the self-tapping screw 20 inserted into the
screw hole 18' provided in the earth Eixing terminal 18.
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As described above, the preferred embodiment of
the present invention provides the connector 12 with the
groove 15 which is engaged with the edge of the opening
formed in the wall of the main unit in addition to the
three plastic-moulded lines of the AC power cord,
including the earth line, and the earth fixing terminal,
which is integrally formed and held inside the connector
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and connected to the earth line. Consequently, the AC
power cord connector is securely installed to the main
unit by externally securiny the earth fiY~ing terminal to
the wall of the main unit via the screw and washer. This
allows the earth line of the AC power line to be simul-
-~a~7 e o ,,~s /Y
grounded onto the main unit, thus making it pO5-
sible to easily and securely intall the AC power cord.
In the preferred embodiment of the presen-t in-
vention shown in Fig. 2, it should be noted -that, since
such portions located between the earth terminal 18 of
the connector 12 and the rear panel 7 are totally composed
o~ plastic material, i-t is probable that the installed
earth terminal 18 may be loosened as time goes by due to
degradation of plastics, which will eventually cause the
earth to incorrectly function.
In Fig. 4, in which parts iden-tical to those
which are shown in Figs. 1 through 3 are indicated by -the
identical reference numbers, reEerence number 31 indicates
a reinforcement sleeve composed of metal, e.g. brass, which
either has a rough surface or a knurled surface 310 as
shown in Fig. 5. The sleeve 31 is internally held by the
screw in a posi-tion between the earth terminal la and the
rear panel 7 of the connector 12 and acts as a reinforcing
unit concentric with the screw hole 32. ~he metal sleeve
31 may be orcibly inserted into position in the bushing
unit 12 after the formation of the connector 12. However,
it is preerable to install the metal sleeve 31 when form-
ing the connector 1~ in order to improve productivity.
Using the metal sleeve 31, even if the plastic
material located between the earth terminal 18 and the
rear panel 7 becomes degraded, the earth terminal can be
securely held by the reinforcing effect of the metal sleeve
: 31, thus preventing the earth from improperly functioning.
In addition, since the knurling 310 is formed around the
metal sleeve 31, the metal sleeve is always tiyhtly held
against the plastic material of the connector, and as a
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result, even the slightest slack can be securely preve}~ted.
Such a sleeve may be composed of a metal other than brass
or it may be composed of any suitable mate~ial other than
metal.
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